A generic thermoelectric module is known for example from DE 10 2013 214 988 A1 or from EP 2 159 854 A1. Such a module comprises a plurality of thermoelectric elements which are arranged spaced apart from one another between a hot side of the module and a cold side of the module. Furthermore, a plurality of conductor bridges are provided for electrical interconnection of the thermoelectric elements as well as for contacting with electrical connections of the module. A hot-side substrate forming the hot side consists of an electrically insulating material or has an electrical insulation on an inner side facing the thermoelectric elements. Similarly to this, a cold-side substrate forms the cold side and consists of an electrically insulating material or has an electrical insulation on an inner side facing the thermoelectric elements. In the thermoelectric module known from EP 2 159 854 A1, an electrically insulating holder is additionally known for positioning the thermoelectric elements between the substrates wherein the holder for each thermoelectric element comprises a separate through opening into which the respective thermoelectric element is inserted.
Thermoelectric elements consist of thermoelectric semiconductor materials which convert a temperature difference into a potential difference, i.e. into an electrical voltage, and conversely. In this way, a heat flow can be converted into an electrical current and conversely. Thermoelectric modules are based on the Peltier effect when they convert electrical energy into heat and on the Seeback effect when they convert heat into electrical energy. Inside a thermoelectric module, p-doped and n-doped thermoelectric elements are interconnected. Usually a plurality of such thermoelectric modules are interconnected to form a thermoelectric generator which can be used for cooling or heating depending on the energization or can generate an electrical current from a temperature difference combined with a corresponding heat flow.
For example, these thermoelectric modules or thermoelectric generators can be used in internal combustion engines, in particular in motor vehicles, for recovering waste heat, for example, in order to convert waste heat contained in the exhaust gas into electrical energy. Problems with such applications are the temperatures which vary within a large temperature range combined with the requirement that the most efficient possible heat transfer within the thermoelectric module is desired between the thermoelectric elements and the substrates whereas at the same time, an electrical insulation must be provided at this point. Materials which are good thermal conductors usually have a poor electrical insulation. Furthermore, materials which are thermally good insulators usually have a poor electrical conductivity. Furthermore, the varying temperatures result in thermally induced expansion effects which give rise to relative movements of the individual components within the thermoelectric module. Such relative movements can increase the mechanical loading of the thermoelectric module. These thermomechanical loadings adversely affect the lifetime of such a thermoelectric module. The thermomechanical loadings occur on the one hand between the thermoelectric elements and the conductor bridges and on the other hand between the conductor bridges and the substrates. Furthermore, these thermomechanical loadings also occur between electrical contacts and the associated conductor bridges.